refactor to mautrix 0.17.x; update deps

vendor/maunium.net/go/mautrix/crypto/olm/utility_goolm.go

@@ -0,0 +1,92 @@
+//go:build goolm
+
+package olm
+
+import (
+	"crypto/sha256"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+
+	"github.com/tidwall/gjson"
+	"github.com/tidwall/sjson"
+	"go.mau.fi/util/exgjson"
+
+	"maunium.net/go/mautrix/crypto/canonicaljson"
+	"maunium.net/go/mautrix/crypto/goolm/utilities"
+	"maunium.net/go/mautrix/id"
+)
+
+// Utility stores the necessary state to perform hash and signature
+// verification operations.
+type Utility struct{}
+
+// Clear clears the memory used to back this utility.
+func (u *Utility) Clear() error {
+	return nil
+}
+
+// NewUtility creates a new utility.
+func NewUtility() *Utility {
+	return &Utility{}
+}
+
+// Sha256 calculates the SHA-256 hash of the input and encodes it as base64.
+func (u *Utility) Sha256(input string) string {
+	if len(input) == 0 {
+		panic(EmptyInput)
+	}
+	hash := sha256.Sum256([]byte(input))
+	return base64.RawStdEncoding.EncodeToString(hash[:])
+}
+
+// VerifySignature verifies an ed25519 signature.  Returns true if the verification
+// suceeds or false otherwise.  Returns error on failure.  If the key was too
+// small then the error will be "INVALID_BASE64".
+func (u *Utility) VerifySignature(message string, key id.Ed25519, signature string) (ok bool, err error) {
+	if len(message) == 0 || len(key) == 0 || len(signature) == 0 {
+		return false, EmptyInput
+	}
+	return utilities.VerifySignature([]byte(message), key, []byte(signature))
+}
+
+// VerifySignatureJSON verifies the signature in the JSON object _obj following
+// the Matrix specification:
+// https://matrix.org/speculator/spec/drafts%2Fe2e/appendices.html#signing-json
+// If the _obj is a struct, the `json` tags will be honored.
+func (u *Utility) VerifySignatureJSON(obj interface{}, userID id.UserID, keyName string, key id.Ed25519) (bool, error) {
+	var err error
+	objJSON, ok := obj.(json.RawMessage)
+	if !ok {
+		objJSON, err = json.Marshal(obj)
+		if err != nil {
+			return false, err
+		}
+	}
+	sig := gjson.GetBytes(objJSON, exgjson.Path("signatures", string(userID), fmt.Sprintf("ed25519:%s", keyName)))
+	if !sig.Exists() || sig.Type != gjson.String {
+		return false, SignatureNotFound
+	}
+	objJSON, err = sjson.DeleteBytes(objJSON, "unsigned")
+	if err != nil {
+		return false, err
+	}
+	objJSON, err = sjson.DeleteBytes(objJSON, "signatures")
+	if err != nil {
+		return false, err
+	}
+	objJSONString := string(canonicaljson.CanonicalJSONAssumeValid(objJSON))
+	return u.VerifySignature(objJSONString, key, sig.Str)
+}
+
+// VerifySignatureJSON verifies the signature in the JSON object _obj following
+// the Matrix specification:
+// https://matrix.org/speculator/spec/drafts%2Fe2e/appendices.html#signing-json
+// This function is a wrapper over Utility.VerifySignatureJSON that creates and
+// destroys the Utility object transparently.
+// If the _obj is a struct, the `json` tags will be honored.
+func VerifySignatureJSON(obj interface{}, userID id.UserID, keyName string, key id.Ed25519) (bool, error) {
+	u := NewUtility()
+	defer u.Clear()
+	return u.VerifySignatureJSON(obj, userID, keyName, key)
+}